Recently, the Internet has been widely spread, and users can access various information in websites around the world to obtain the information. In accordance therewith, devices capable of broadband access such as ADSL (Asymmetric Digital Subscriber Line) and FTTH (Fiber To The Home) have also become rapidly widespread.
Related art techniques relating thereto include techniques disclosed in Patent Document 1 and Non-Patent Document 1 below. In an office-side line concentration device disclosed in Patent Document 1, a buffer memory, a receiving unit, a transmitting unit, and a PON IF (interface unit) are provided for each of a plurality of PON transmission lines A, B, . . . , and Z. A control unit generates control frames so that normal frames received via the PON transmission lines A, B, . . . , and Z do not conflict, and sends the control frames to the PON transmission lines A, B, . . . , and Z.
Further, Non-Patent Document 1 specifies EPON access control protocols (MPCP (Multi-Point Control Protocol)) and OAM (Operations, Administration and Maintenance) protocols, and describes a method for registering a new home-side device using MPCP messages, bandwidth allocation requests, transmission instructions, and the like.    Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-253881    Non-Patent Document 1: IEEE Std 802.3ah (registered trademark)-2004